Phospholipase A2, Group XIIB (PLA2G12B)

The predicted 195-amino acid human protein shares 90% identity with the mouse protein and 40% identity with human PLA2G12A. It contains a 19-amino acid signal peptide and 14 cysteines, but it lacks N-glycosylation sites and has a leucine in place of the canonical histidine in its active site.

PLA2G12B is conserved in vertebrates, but not in invertebrates. SDS-PAGE revealed a 20-kD PLA2G12B protein, consistent with the calculated molecular mass of the mature protein. Northern blot analysis detected 1.4- and 6.5-kb PLA2G12B transcripts in liver, kidney, skeletal muscle, and heart. Expression of PLA2G12B was significantly weaker in tumors of kidney, liver, and small intestine compared with matched normal tissues. PLA2G12B expression varied in cancer cell lines.